Cocked damping mechanism

ABSTRACT

A digital hydraulic system converts binary digital input information into displacement of a digital drive. An air reader is used to operate binary latch valves through an air hydraulic interface. A flow sensing system and a hydraulic logic unit cooperate to provide high speed exchange between the piston adders of the digital drive prior to displacement of the load. A hydraulic cylinder sweeps the load about a vertical axis. A selfcooling, air-driven hydraulic pump with an accumulator, provides relatively constant pressure. A damper secured to the piston adders has an additional drive for providing precise location at the end of damping. An incremental paper tape feed with a four motion rack with toggle action indexes the air reader.

United States Patent Panissidi Mar. 12, 1974 COCKED DAMPING MECHANISM 75Inventor: Hugo A. Panissidi, Peekskill, NY. f Geoghega AssistantExammerAllen M. Ostrager [73] Assignee: International Business MachinesA or Agent, or Firm Grah S. Jones, ll

Corporation, Armonk, NY. 22 Filed: Mar. 20, 1972 [571 1 ABSTRACT Adigita hydraulic system converts binary digital input [211 App! 236520information into displacement of a digital drive. An air Related US,Application D t reader is used to operate binary latch valves through[62] Division of Sen 824,424, May 14 1969 Pat NO. an air hydraulicinterface. A flow sensing system and a hydraulic logic unit cooperate toprovide high speed exchange between the piston adders of the digital 52us. Cl. 91/167, 92/9 drivc prior to displacement of thc lcad- Ahydraulic [51] I (1 15 1 1 cylinder sweeps the load about a verticalaxis. A self- 58 Field of Search 92/8, 9, 10, 11; 91/167 cooling,air-driven hydraulic P p with an accumulator, provides relativelyconstant pressure. A damper 5 References Cited secured to the pistonadders has an additional drive UNITED STATES PATENTS for providingprecise location at the end of damping. 4 An incremental paper tape feedwith a four motion E53 Z rack with toggle action indexes the air reader.3,476,266 11/1969 Devoi 11 92/9 X 7 Claims, 17 Drawing Figures 114i ;l42.;l4i [J42 EH I42 Ml M2 {98 /200 75 I47 155 Z i 1/2 /4 us me r200PAIEIIIEIIIImIw afrssdaz SHEET '01 or 14 FIG. 1

TAPE I? 14 SWITCHING 15 I I" I4I,I42 HYDRAULIC I2 VELOCITY BINARY AIRAIR CONTROL LATCH HYDRAULIC VALVE VALVES |NTER|=ACE READER RESET 7 88PROBE \OPERATE 542x I4I,I42 116 X TOGGLE H5 DRIVE RACK 16 EII FE 52 W ToA QQ'JE HYDRAULIC N DAMPER FLOW POWER ADDERS 5 SENSING SUPPLY 156 j {881M SYSTEM 75 76/ MFA s? 5 -BLEED H6 CONTROL HYDRAULIC LOGIC START I iON-OFF /94 DECODER I WITH ALIGNERS TREE |83 L51 25 52/ CLAMP 200 19aRACK BLEED I r I 53\ I 206 f SWEEP 196 54 S SENSE u SWEEP g \SWEEP km RSENSE T PAYENYEDAAA 12 1974 3; 796; 132

SHEET 12 F 14 FIG. FIG. F|G-3 3A 3B FIG. 3A

1 lsoLAnol vALvE o- DISPLACEMENT IN' INCHES PURGE CONTROL vALvEo-L0AD1"- VELOCITY CONTROL vALvE0- READER RACK PISTON0 READER TOGGLEvALvED- ALIGNER PISTON 0- ALIGNER. vALvEo- ALIGNER DELAY P|STON0 ALIGNERLATCH VALVE0- DAMPER PISTON o DAMPER DELAY P|STON0 DAMPER VALVE0-EXCHANGE mm 0- MOVE vALvE 0- MOVE SENSE vALvED- EXCHANGE SENSE VALVE0-BYPASS P0PPET(1 1" CYLINDER 0- o.1 LATCH VALVE0 2" CYLINDER-' N0.2 LATCHVALVE0 N0.2 PILOT vALvEo- MOVE DELAY P|STON0- FLOW VALVE 'o- FLOWVVALVEPISTON0 START VALVE o- PROBE VALVE 0- PROBE DELAY P|STON-0- PROBE PHASEP|$TON0- TIME IN MILLISECONDS PATENTEDHAR 12 I974 saw 13 OF 14 FIG. 3B

IlllIlllIlIlIlIlIIlIIIIIIIIIII TIME IN MILLISECONDS- skrssLma ISOLATIONVALVE PURGE CONTROL VALVE LOAD VELOCITY CONTROL VALVE READER RACK PISTONREADER TOCGLE VALVE ALIGNER PISTON ALICNER VALVE ALIGNER DELAY PISTONALICNER LATCH VALVE DAMPER PISTON DAMPER DELAY PISTON DAMPER VALVEEXCHANGE VALVE MOVE VALVE MOVE SENSE VALVE EXCHANGE SENSE VALVE BYPASSPOPPET I" CYLINDER NO. I LATCH VALVE 2" CYLINDER NO.2 LATCH VALVE NO.2PILOT VALVE MOVE DELAY PISTON FLOW VALVE FLOW VALVE PISTON START VALVEPROBE VALVE PROBE DELAY PISTON PROBE PHASE PISTON PAIENTEDNAR 12 m43.796; 1132 saw u nr 14 COCKED DAMPING MECHANISM This is a division, ofapplication Ser. No. 824,424 filed May 14, 1969 now U.S. Pat. 3,726,190.

CROSS REFERENCE TO RELATED APPLICATIONS This application is related tocopending U.S. application Ser. No. 694,941 by I-I.A. Panissidi entitledManipulator, U.S. Pat. No. 3,550,630 issued on application Ser. No.695,139 by I-I.A. Panissidi entitled Serial-to-Parallel HydraulicDevice, and U.S. Pat. application Ser. No. 824,425 now U.S. Pat. No.3,641,877 entitled Flow Sensing System and Valve by R. C. Hebert, filedherewith.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to damping devices. More particularly, this invention relates todamping devices which are secured to a digital drive mechanism.

2. Description of the Prior Art Conventional damping mechanism maycontain springs or other means for returning the damper'to a zero orneutral position. However, previously known damping mechanisms in theart have not included any means for precisely locating the moveablemechanism relative to a fixed member. Accordingly, in connection withaccurate digital drives, it is highly desirable to provide some meansfor providing damping and at the same time including control mechanismand means for precisely locating the load at the end of the displacementcycle.

Prior air driven engines have toggled relatively slowly thereby causinga fairly high degree of regulation or fluctuation in output pressurefrom the oil pump. Faster systems have often employed electrical motorswhich have created a significant heat dissipation problem. Externalcooling arrangements have been supplied for such systems includingradiators, circulation of oil to the radiators on the exterior of thesystem. Such radiators require space and are costly.

location. In connection with digital drives, means are provided ofaccurately locating the first member of the digital drive relative to azero position after each operation of the digital drive to displace theload in a predetermined direction has been accomplished. In anotheraspect, means are provided for initially cocking the damping mechanisminto a position in the opposite direction from the final direction ofdisplacement. Subsequently, upon deceleration by the damper with minimumovershoot, the load is caused to locate by positive locating means inthe damper.

An object of this invention is to provide accurate location of a digitaldrive subsequent to the major displacement motion of that drive anddamping thereof.

A further object of this invention is to provide means for efficientdamping of a drive subsequent to displacement of the load.

A related object is to provide damping with minimum overshoot.

An object to this invention is to provide means for reversing thedirection of operation of an air engine prior to the time that the pumpbeing driven thereby reaches its extreme position.

The foregoing and other objects, features, and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention, as illustratedin the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a schematic block diagramof the overall system employed in accordance with this invention.

FIG. 2 shows the relationship between the various sections of the largediagram of FIGS. 2A-2K. FIGS. 2A-2K show the overall connections betweenthe various subsystems of the integrated adder drive assembly employedin accordance with this invention, and in FIGS. 2K and 2L additionaldetails of the system are shown.

FIG. 3 shows the relationship between FIGS. 3A and 3B.

FIG. 3A and 3B show the displacement characteristics of valves andmechanism in the hydraulic system shown in FIGS. 1 and 2A-2K inaccordance with this invention as a function of time.

FIG. 4 shows the sweep and arm clamping mechanisms for the base of amanipulators arm.

- DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT CONTROL SYSTEMReferring to FIG. 1, the present system includes an air reader 10 forreading a perforated tape 11 which provides output pulses to a hydrauliccontrol system by means of an air line 12 and an air hydraulic interface13 which converts pneumatic pulses to hydraulic values. The airhydraulic interface transfers pulse inputs to hydraulic binary latchvalves 14 which remember or retain a O or a 1 condition, depending uponthe sense or polarity of the input transmitted from reader 10 throughthe interface 13.

The outputsof the latch valves are in general connected via lines 141,142 to extend or retract a corresponding one of several piston adders 15which comprise a series of interconnected pistons and cylinders employedto provide binary displacement of a load bearing shaft 156 by unitdistances, in binary progression from from one thirty-second inch toalmost 32 inches in binary steps up to 16 inches.

For the l, 2, 4, 8 and 16 inch long piston adders, a set of variableorifices in a velocity control valve 17 are provided between lines 141,142 and 342 for the purpose of controlling the rate of displacement ofthe pistons with larger displacements.

In order that the piston adders 15 and the output shaft 156 connected toone end thereof may be accurately located rapidly, a damper 18 isprovided which permits the piston adders 15 to be cocked during anexchange interval.

The exchange interval is a time during which the output shaft 156 isfirmly retained in position by braking or arresting means shown in partherein and shown in full in above U.S. Pat. No. 3,575,301 and the pistonad- 7 ders 15 are reset and extended to the extent that certain pistonsare retracted and certain other pistons are extended. During theexchange" period the velocity control valve 17 will be held wide open topermit exchange at maximum permissable velocity, since the piston adders15 will not be under load.

Referring again to the damper 18, when the load has provides hydraulicdamping with minimum overshoot and is actuated via line 75 by hydrauliclogic unit to provide mechanical positioning ultimately to a precisehome position. Cocking minimizes overshoot and optimizes use of time forthe steps of exchanging piston locations and driving the load.

In order to provide regulated hydraulic pressure to the system ahydraulic power supply 22 is provided. It supplies pressure for latchingand to the central lands 16 of spool valves in the hydraulic logic unitvia line 116 and the flow sensing system 23, via line 47, which controlstwo bleed lines 24 and to the hydraulic logic unit 20 as a function ofthe velocity of flow through line 47, the flow sensing system 23 andline 52 to the latch valves 14 which connect to the piston adders 15.When the flow or displacement of piston adders declines below a minimumvalue the bleed lines 24 and 25 are blocked by flow sensing system 23. Abypass control line 38 from the hydraulic logic unit 20 controls a port40, 41 inside the flow sensing system 23 to control one of the flowsensing units therein.

. grooves 45 with the bleed lines 24 and 25, thereby con- The hydrauliclogic unit 20 can be started and stopped. Since the logic unit 20controls the toggle line 76 which powers the feed advance of the tapereader 10, when switch 54 is operated, air is blocked from op eratingthe logic unit 20 and at the end of a displacement cycle operation ofthe system stops.

As the drive is adapted to displace a plurality of members, a decoder isconnected to the logic unit 20 via line 94, and to certain ones of thelatch valves 14, to operate aligners 31 to hold the various members tobe displaced by the output shaft, through a linkage, not shown, which issimilar to that shown in copending U.S. Pat. No. 3,575,301. Clamp rack33 is engaged when it is desired to drive the Z arm of the output, forexample, a manipulator, as shown in FIG. 4.

A set of sweep sense units 33 and a sweep cylinder 34 are employed tosweep a load on support 190 about an axis upon an input via line 198 or200 from one of the latch valves 14. The sweep sense unit 33 isconnected to bleed line 25.

Referring to FIGS. 2A-2J, the overall system is shown in greater detailthan in FIG. 1 and the connections between the various systems areshown.

EXCHANGE AND VARIABLE VELOCITY CONTROL The exchange and move flowsensing system 23 includes a cylindrical exchange sense piston 35, acylindrical move sense piston 36 and a bypass poppet 37. The bypasspoppet 37 is controlled by pressure in a line 38 connected to the loweroutput of flow spool valve 39 in FIG. 2B. When the bypass poppet 37 isto the left, its valve 40 will seat on surface 41 to close off the inlet42 to the exchange sense piston 35. It should be noted that the exchangesense piston and the move sense piston 36 are each spring biased bysprings 43, coaxial therewith in the larger coaxial bore 44 in thepistons 35 and 36. The pistons 35 and 36 are grooved at 45 to connectthe bleed lines 24 and 25 to the return 46 to the low pressure side ofthe hydraulic pressure supply 22. Pressure from the hydraulic pressuresupply 22 is supplied by line 47 to the inlet 48 on the upstream end ofthe valve of the bypass poppet 37 which may or may not be open, asdescribed above, and to the inlet 49 to the move sense piston 36. Eachof the exchange sense piston 35 and the move sense piston 36 is providedwith necting the bleed lines to return 46. The by-pass poppet 37provides a means for selectively actuating the exchange sense piston 35.In this way, the flow sensing system may be operated in two modesdepending on whether the piston adders 15 are being driven in the moveor exchange mode of operation. A further feature of this system is thatsince each of the orifices 50 is substantially of the same order ofmagnitude in diameter and length, the resistance to fluid flow providedby each thereof is substantially of the same order of magnitude. Whenboth are connected in parallel, the resistance to flow is nearly halved,or conversely, flow doubles, approximately. As will be noted, theoutlets 51 of the two sense pistons are connected to line 52. Since thetwo sense pistons are in parallel, and therefore the orifices 50 are inparallel, if the bypass valve 46 is open, the quantity of flow througheach of the two orifices 50 will be substantially equal and accordinglythe rate of flow into the line 52, if sufficiently large andunrestricted will in general be approximately doubled. Accordingly, whenthe exchange sense piston 35 is permitted to operate by the bypasspoppet 37, the quantity of fluid flowing from lines 51 through line 52to the piston adder drive will be greater and the velocity ofdisplacement in the exchange period will accordingly be far greater.(See U.S. Pat. No. 3,641,877 for a more complete description under thissection).

HYDRAULIC LOGIC UNIT The hydraulic logic unit comprises a plurality ofspool valves, delay pistons in cylinders which comprise compliance orcapacitive units which require a time delay for displacement from oneend to the other end of the cylinder in which they are housed; orifices,check units described below in connection with FIG. 2L, interconnectionsand outlets which control other elements of the overall system. Certainof the spool valves are spring biased into one position as indicated byhelical springs in longitudinal cross section. Certain other of thespool valves are latch valves which are held in position by hydrauliclatching means. Such a latching means comprises a passageway 600tangential to one end of a land of a spool located so that it suppliesfluid under pressure to the side of the land regardless of spoolposition, and contacts a small area on one side. The land therebycreates a laminar pressure gradient along that side which is coupled tothe return lines through leakage. There is a ratio of pressures acrossthe land of several times the pressure on the inlet side to the pressureon the low pressure side which pushes the land to one side and inhibitslongitudinal sliding because of friction forces. Pressure can be relievdduring movement of the spools to relieve friction forces.

When the start diaphragm 56 is operated by the pressure at inlet 53(assuming pneumatic toggle 54 is on) from the reader start apertures 28in the tape via line 29, or otherwise provides input from a two waysolenoid or valve 27, etc. then the start spool valve 55 is drivenupwardly thereby connecting its lines 57 to the right and to the left tohigher pressure from the central annular groove 16 as the central landor ring passes therabove. Accordingly, pressure will be applied at thejunction 58 between the orifice checks (described below in connectionwith FIG. 2L, 59 and 60 which connect to the probe spool valve 61, theprobe delay piston 62, and the probe phase piston 63. On the left side,the line 57 is connected to the point 64 which supplies the lower end offlow spool valve 39; and by orifice check 65 point 64 is connected toline 66 and phase piston 67. It will be noted that line 66 is connectedto bleed line 25 and both are connected to the upper end of the flowspool 39, valve which is spring biased downwardly. Accordingly, when theflow phase piston 67 has moved fully to the top of its cylinder at theend of 60 milliseconds, then as soon as the exchange sense valve causesthe bleed line 25 to be disconnected from the return 46, the pressure onthe line 25, and therefore on the upper end of the flow spool valve willbe increased and the flow spool valve will be driven back to itsposition as shown in FIG. 2B by the force of the spring 87. Initially,then, as soon as the start valve is operated, the flow valve will beoperated also and pressure will be placed upon line 38 from the centralhigh pressure source and line 38 will connect pressure to the bypasspoppet, which will remain open until the flow valve is driven back toits home position. Since line 38 is connected to the lower end of delaypiston 68 and to the lower end of move spool valve 69 which is biasedupwardly, the move valve will be driven rather rapidly upwardly shortlyafter the flow valve is driven upwardly, by the spring 53. It should benoted that later, when flow is reversed, the delay piston 68 cooperateswith the orifice check 70 to provide a long time delay before it ispossible for the move valve 69 to be reset down against the force of itsspring 53. When the move valve is driven upwardly, the line 71 from theupper end thereof has the pressure thereon released, thereby releasingpressure on the upper end of the exchange spool valve 72 which will havepressure on the lower end thereof from the line 38 which, after thedelay valves have permitted the pressure to build, will then shiftupwardly. The damp spool valve 73 has a spring bias at the lower endthereof, and will shift shortly after the exchange valves shifts, thusreleasing the pressure from the uper end thereof. Line 75 is connectedto the damper 18 including its pistons as shown in FIG. 1 and FIG. 2Jsecured to one end of the piston adders 15. At this point in eachdisplacement cycle of the drive, pressure is released from the damperpositioning pistons 80. Accordingly, the damper is released so that itcan be cocked during the exchange mode of operation. After an intervalof about milliseconds selected to allow pilot valves 85 to bepositioned, according to the data in the tape, the probe delay piston 62will have reached the opposite end of its cylinder. Accordingly,'thepressure at the lower end of the probe spool valve 61 will have reacheda high enough level to overcome the spring biasing force at its upperend and to drive the valve upwardly thereby providing pressure on probeline 81 from the central annular pressure source 82 as the central landpasses thereacross and the lower land passes across the return 83. Theprobe line 81 is connected to each of the inlets 84 of the pilot valves85 to provide pressure to their central annular cavities. The probepressure is employed to adjust the hydraulic binary latch valves 14 inaccordance with the binary valves provided by the air reader 10. Thus,the

binary drive will be reset in accordance with the most recent input dataprovided thereto in the tape under the air reader 10. It will beunderstood that another variety of input source could be connectedthrough a suitable interface. About 40 milliseconds after start, theprobe phase piston 63 will rise to the top of its somewhat longercylinder and at that time will cause a pressure build up at its lowerend, which is connected to the upper end of the probe spool valve 61which is spring biased downwardly. Since the presures of the oppositeends of the probe spool valve 61 will be equal and opposite,accordingly, the probe spool valve will be driven downwardly by itsspring 86. At this time pressure will be removed from the probe line 81.This will not mean the end of the exchange motion of the piston adderswhich will be under control of the hydraulic latch valves 14 which willremain as positioned during the probe portion of the control cycle ofthe hydraulic logic circuit 20. So long as the exchange continues, theexchange sense piston 35 will remain in its upper position against itsspring as will the movesense piston. At a predetermined point, when theexchange velocity ends and the flow of hydraulic fluid due toelimination of pressure differential and the end of flow through thesense pistons 35 and 36, they will both move down to their spring biasedlower positions. Accordingly, bleed line 24 will be closed momentarilyand bleed line 25 will be closed for the remainder of each cycle ofoperation of the hydraulic logic unit 20. Line 25 will thereby causebuild up of pressure on the upper end of the flow valve 39 as mentionedabove and the spring 87 at the top thereof will act to drive the flowvalve 39 down. Pressure will build on the line 24 and line 89 from lines16 and 688 through the flow valve 39. However, the delay piston 68 andthe orifice in orifice check will deferthe build up of the pressure inthe lines 24 and the build up of the inlet 89 to move valve 69, andactually the move valve 69 will not be operated at this time, because, ashort time later, bleed line 24 will be reconnected by move sense piston36 to the return 46 and will bleed pressure from inlet 89. Line 688 willapply pressure immediately to the central cylindrical cavity 188 of theexchange spool valve 72 held up by pressure in line 38 and therebyproviding pressure on line 90 to the lower end of the aligner latchvalve 74. The aligner latch valve 74 will be driven upwardly since theupper end thereof will have low pressure, as on line 75. The pressurehad been released as described above. Ac cordingly, the aligner latchvalve will release pressure on line 91 to permit the aligner spool valve92 to be driven upwardly by a spring 93. This will apply pressure toline 189 resetting start spool valve 55 applying pressure from line 116to reset line 88 to reset all of the pilot valves and will releasepressure from line 94 which is connected to the aligners 31 so that oneof the members connected to the output of the load shaft can be drivenat this point. Further, line 94 is also connected to the velocitycontrol valve 17 in order to reduce the orifice into the piston addersduring the period of driving of the load. As the load is now free tomove, the piston adders can move and accordingly flow will resume inline 52 (as indicated above in connection with line 24) and for thatreason the pressure drop across the move sense piston will resume andthe move sense piston will be driven upwardly again thereby bleedingpressure from the bleed line 24. However, the bypass poppet 37 will havepressure released therefrom on line 38 since the flow valve 39 will, asdescribed above, have been driven downwardly thereby connecting line 38to the return 95. Pressure on line '76 from aligner latch valve 74 inFIG. 2A to the reader 10, FIG. 2D, will operate the reader feedmechanism. In addition, in the purge control in FIG. 2B, pressure inline 76, will operate a pair of pistons 96 from line 97 attached to theline 76 to drive the spool valves 98 and 99 to the left so that thepressure on line 100 will be connected down into the lines 101 which areconnected to the purge inlets to the diaphragms 102 in the air hydraulicinterface 13. Air under psig pressure will be driven through the purgeinlets 101 across the surface of the diaphragms of the interfaces 102and out through the reader lines 12 to purge or to drive oil out of thesystem and to clear and chad and other material from the lines 12, and112. The remainder of the purge cycle is described below, afterdiscussion of concurrent valve operations.

The pressure will remain on line 76 until such time as the motion of thepiston adders ends and the move valve 69 is driven downwardly in finalclosure of the bleed line 26 by closure of the move sense piston 36, sothat at that time, line 71 will drive the exchange valve 72 downremoving pressure from line 90 and at the same time applying pressure toline 103 through the orifice of orifice check 104 and delay piston 105after a time delay of 90 milliseconds, drive the damp valve 73 downagainst its spring and to apply pressure on line 75 therefrom to drivethe aligner latch valve 74 down and remove pressure from line 76 andapply pressure to line 91 and through the orifice in the orifice check106 and delay piston 107 cause a time delay to run to drive the alignervalve 92 down against its spring 93. The aligner delay piston 107 willrequire another 120 milliseconds to drive downwardly. Accordingly, finalalignment will not occur for some time.

However, referring again to the purge unit, in FIG. 2B, when line 71 ispressurized, the piston 99 will be driven to the right and atmosphericpressure from line 199, to atmosphere, will be permitted to resumeinside the purge and reader lines 101 and 12 so that the diaphragms 102may be returned to atmospheric pressure. Then when pressure is removedfrom line 76 as a result of return of the aligner latch value to itslower position, the spring 108 of the spool valve 98 will act to drivethat spool valve to the right and to shut off connections 101 to thediaphragms. It should be noted that the 10 psig air supply 109 isconnected to line 110 which applies positive pressure to the airpressure head 111 for passage through the tape 1 1 into the inlets 12 tothe diaphragms 102.

During the time that the purge spool valve 98 is to the left, theblocking of pressure by valve 98 from line 110 to the air reader 1 1 1will prevent blowing air down into the diaphragms during the purge cyclewhen air is to be blown in the reverse direction.

AIR READER The perforated tape reader shown in FIG. 2D will operate inordinary machine shop air typical of industrial locations, which iscontaminated with dirt, oil and water. Therefore, cyclic purging oflines 12 is necessary because the reader sense hoses are extremely thin,usually 0.03O inches I.D. making them vulnerable to cloggmg.

In order to avoid costly memory devices and serial to parallelconverters for some applications, the reader is designed to advance thetape up to two characters per step, allowing the system to accept twocharacters of data simultaneously. The hydraulically driven reader, asshown schematically, consists of an air reader head filifi pdrts toaccept two perforated characters of an 8 channel Mylar tape. The 16ports of the air reader head are connected by sense hoses to the 16diaphragm driven hydraulic pilot valves. The air reader head,suppsaiagthampa is pressiirized with 10 "bsi'gatrs spring loaded airmanifold. A hole in the tape will allow its corresponding diaphragmactuated pilot valve to be pressurized with 10 psig from the airmanifold.

The air reader 10 includes an air pressure head 111 which is springbiased downwardly by a spring 117. The tape which is used includes 8longitudinal columns and is read in groups of two rows of characterssuch, as shown in FIG. 2D, simultaneously. Accordingly, the feed mustadvance two rows of holes for each reading cycle. The top hole in thefirst row is the start control. The next two holes are M2 and M1controls for FIG. 2E and the next holes ones are the fractions fromonehalf inch down to one thirty-second inch. In the second column in thesecond hole, the sweep mode of operation of the manipulator which wouldbe attached to the device is entered and in the third hole, the bit forthe grip mode of operation of a manipulator gripper would be entered. Inthe last five holes in the second column, the bits'for the l6, 8, 4, 2,and 1 inch piston adders would be entered. The head 111 is designed soas to provide air pressure above all 16 holes and underneath the holeswould be aligned the various inlets 12 to the diaphragms 102 shown inFIGS. 2E-2H. The feeding mechanism is comprised of a sprocket wheel 118which operates in cooperation with perforations 119 in the tape 11. Thesprocket wheel 118 is secured to shaft 120 and the shaft 120 isjournalled for rotation in response to torque applied by gear 121 whichis retained in position by detent pawl 122 which is spring biaseddownwardly by spring 123. The pawl 122 carries a pin 124 at one endthereof which fits into the teeth of gear 121. The gear 121 is adaptedto mesh with a rack 125 which can be raised into gear by a toggle lever126 which is pivotally secured by pin 127 in which toggle lever carriesrack 125 on pin 128. The rack 125 is reciprocably longitudinallyslideable on drive wire 129 secured at its distal end to a piston 130slideably carried in cylinder 131 for longitudinal reciprocationtherein. The cylinder 131 contains a spring 132 at the distal end of thepiston 130 for biasing the piston 130 leftwardly. At the opposite end ofthe cylinder is a release aperture 333 to permit motion to the right.The opposite end of the toggle lever 126 is secured to a drive wire 133by means of pin 13% to bifurcated end 135 of drive wire 133. Drive wire133 is secured at its distal end to a spool valve 136 carried incylinder 137. The spool valve 136 is spring biased leftwardly by spring138. At the leftward end of piston 130 is an inlet 139 connected fromthe central portion of cylinder 137 adapted for communication with thetwo inlets 81 and 281 into the lower cylinder 137 from the centralportion thereof. At the leftward extreme end of cylinder 137 is locatedan inlet from line 76 from the aligner latch valve lower outlet, whichis provided for operating the reader. lf pressure were applied to line76, it would function to pull the toggle lever 126 counterclockwiseabout pin 127 by means of flexing of drive wire 133. Lever 126 and pin128 will drive the rack 125 up into engagement with the gear 121preparatory to actual driving motion. When this occurs, i.e., valve 77is to the right, the connection of line 139 to the cylinder 137 will bemade to the line 116. This will drive the piston 130 to the rightagainst the reaction of its spring 132 pulling wire 129 and the rack 125to the right and turning the gear 121 counterclockwise about shaft 120thereby advancing the tape 11 two character positions to the left as thesprocket 118 is turned on the shaft 120 counterclockwise. It should benoted that while the probe pressure is employed for the purpose ofdriving the air reader, that such probing does not occur until after thepressure on the purge line 76 has been generated by means of driving thealigner latch valve 74 to its upper position after the exchange isterminated. The adjustment of the pilot valves during the probe cyclewill have been completed well prior to that time; and with theapplication of pressure on line 76, and the displacement of the purgespool valve 98 to the left, the pressure applied on line 110 to the airpressure head 111 will have been blocked by the leftward land of thespool valve 98.

During the period the rack rotates the drive gear, there is asubstantial separating force between the rack and gear due to thepressure angle of the gear teeth (20) which is supported by the toggleshaft.

With pressure removed from the left end of the toggle valve, its springwill drive it to the left rotating the toggle lever 126 to its initialposition. The toggle valve will expose port 139 to its port 281, therebyremoving pressure from the left-hand side of the drive piston allowingit and its rack to return to its initial position by the reaction of itsspring.

It is during this tape advance cycle described above that the pilotvalves 85 of the hydraulic system must be physically locked by pressurein line 88 from responding to the tape holes as they move under the airreader head 1 11, and at the same time, the sense hoses 12, diaphragms102 and air reader ports must be flushed out with a reverse air blast topurge the air sense system of any contamination from the previous readcycle. Line 76 to the purge control 99 and isolating valves 98,respectively, causes both valves to move to the left, valve 98 movingagainst the reaction of its spring 108. The transfer of the multipleland isolating valve 98 will expose all of the purge hoses 101 to theport 100 ofthe transferred purge control valve 99 and, at the same time,shut off the air pressure to the air manifold 110 by the scissoringaction of the extreme left-hand land of the isolating valve 98.

The port 100 of the purge control valve exposed to its psig port 109provides a reverse air flow through the 16 diaphragm chambers, sensehoses and the air reader head ports with the foreign matter, if any,being expelled between the air reader head and tape to the atmosphere.Following this purge cycle, the entire reading circuit and diaphragmsmust be depressurized before releasing the locked diaphragm actuatedpilot valves. In order to accomplish the depressurization, the purgecontrol valve must be returned to its initial position before the returnof the isolating valve 98 sealing off all the purge hoses 101.

A time delay network consisting of an orifice in series with move delaypiston 68 controls return of the purge control valve 99 to its initialposition for exposing all the purge hoses to the atmosphere through port281. Again at the end of the tape advance cycle the aligner latch valve74 will be restored to its initial position with the removal of thehydraulic signal, exposing line 76 to the reservoir allowing the tapeadvance circuit and isolating valve to reset to their initial position.

The reset of the isolating valve will permit air pressure to the airmanifold and, at the same time, seal the individual purge hoses toprevent cross talk. With the release of the locking pressure from thepilot valves, it will allow the diaphragms to respond to a hole in thetape causing the transfer of the pilot valve against the reaction of itsspring.

An advantage of the above described pneumatic tape reader is that it hasa minimal number of moving parts, is capable of reading two characterssimultaneously, and in contrast with the type of reader which had beenrequired in connection with this type of system before, eliminates theneed for a character buffer storage unit.

Use of pressure instead of vacuum sensing of the tape holes minimizesthe problem of contamination and costly filtration.

AIR HYDRAULIC INTERFACE From the lines 12 of the air reader 10,connection is made, as described above, to the lines 12 to thediaphragms 102 in FIGS. 2E-2H. When pressure is applied above a hole,then one of the diaphragms 102 will operate to cause its associatedpilot valve to be driven leftward. This will cause the associated latchvalve 14 to be driven leftward also, during the application of pressureto the probe line 81, as the line 84 will be connected to the right-handside of the central land of the pilot valve 85. Accordingly, theright-hand end of the latch valve 14 will have pressure applied thereto.Referring to latch valve 14-16 on the left-hand side of FIG. 2F, thenumeral 14-16 indicates that the latch valve is connected to the 16 inchpiston adder by means of lines 141 and 142. The right hand one of thelines 142 is the one which will have the pressure applied to it in acase in which the pilot valve has been actuated by the reader. It willbe seen that the line 142 passes through the velocity control valve 17in FIG. 21, and if pressure is applied on line 94, then the spool valve143 will be driven to the right and the orifice through the velocitycontrol valve 17 will be reduced for the longer ones of the pistonadders from lengths of 16 inches down to 1 inch. As pressure is appliedthrough line 142, the fluid will flow through line 342 into the space incylinder 145 to the right of piston 144. If the load is released fromalignment or if other pistons are also being displaced at the same time,as in the case of exchange between pistons, then there will be freedomfor the cylinder 145 to move relative to the piston 144, and, of course,since the pressure is applied to the right-hand side of the piston andcylinder, the cylinder will move to the right. In the opposite case, thepiston 144 would move to the left, if the load were released. In FIGS.3A and 3B, a graph is shown of the displacement characteristic for thetwo inch piston adder 146 and the 1 inch piston adder 147. In FIG. 2J,the 1 inch piston adder 147 is shown with its piston 148 extended incylinder 149, whereas the two inch piston adder 146 is shown with thepiston 150 in its collapsed position in cylinder 151. If, for example,it were desired to extend the 2 inch piston adder 146 and to collapsethe one inch piston adder 147 during the exchange period, then theorifice provided by the spool valve 143 in the velocity control valve 17would be retained open and at that time the pressures applied would beon the left-hand

1. In a mechanism having a relatively fixed member, a movable member anddamping means coupled between said movable member and said fixed memberfor exerting a damping force upon said movable member, the improvementcomprising selectively releasable means for positively positioning saidmovable member relative to said fixed member, during engagement of saidreleasable means, said movable member being secured to a first end of anincremental drive and control means for actuating said incremental driveduring an initial interval of time to cock said damping means in thereverse direction of the ultimate direction of travel of said dampingmeans to occur at the end of a driving cycle of said incremental drivewhen damping motion of said movable member, arresting means forarresting the distal end of said incremental drive from said movablemember, said arresting means being affixed relative to said fixed memberat said distal end during cocking of said damping means in the reversedirection from said ultimate direction of travel of said damping means.2. Apparatus including, damping means including a cylinder and a piston,said piston having a shaft secured thereto, an incremental drive havingone of its ends secured to the opposite end of said shaft, and havingthe other of its ends secured to arresting means for selectivelyarresting said incremental drive, and control meAns for controllingoperation of said incremental drive and said arresting means during aninitial interval of time of operaton of said incremental drive causingsaid incremental drive to cock said damping means in the reversedirection from its ultimate direction of travel to occur during aninterval of time subsequent to release of said arresting means.
 3. In amechanism having a relatively fixed member, a movable member and dampingmeans cooperating with said movable member for exerting a damping forcethereon, the improvement comprising selectively releasable means forpositively positioning said movable member relative to said fixed memberduring engagement of said releasable means with said movable member,said movable member being secured to an incremental drive and dampercontrol means for actuating said incremental drive during an initialinterval of time to cock said damping means in the reverse direction ofthe ultimate direction of travel of said damping means to occur later atthe end of a driving cycle of said incremental drive when damping motionof said movable member, means for arresting a fluid system coupled tosaid damping means and said incremental drive for automaticallyarresting said incremental drive by operation of said means forarresting upon the distal end of said incremental drive from saidmovable member, and said damper control means actuating said incrementaldrive to cock said damping means prior to each output motion of saidincremental drive and final control means for automatically engagingsaid selectively releasable means for positively applying forces todrive said movable member into a central position subsequently to eachoutput motion of said system.
 4. In a damping mechanism having arelatively fixed member, a movable member and damping means coupled tosaid movable member for exerting a damping force thereon, theimprovement comprising said damping mechanism including a selectivelyactuated locating means including a piston in a piston chamber forpositively urging said movable member towards a preselected positionrelative to said fixed member during actuation of said piston, saidpiston being mechanically coupled with said movable member by rigidmeans during urging by said piston of said movable member towards saidpreselected position, and control means for controlling the sequenceoperations of said damping mechanism operating said locating meanssubsequent to damping by said damping means said damping mechanismhaving its movable member secured to a load, said control meanspermitting said damping mechanism to provide damping while initiallypassing beyond said preselected position freely and then said controlmeans subsequently providing accurate positioning by actuating saidpiston for driving said load to said preselected position, said movablemember being secured to an incremental drive and during an initialinterval of time said control means actuating said incremental drive tocock said damping means in the reverse direction of its ultimatedirection of travel when damping said movable member.
 5. Apparatus inaccordance with claim 4 including means for arresting said incrementaldrive, said means for arresting restraining the distal end of saidincremental drive from said damping means during said initial intervalof time of operation of said drive for cocking of said damping means inthe reverse direction from its ultimate direction of travel to occurlater.
 6. Apparatus in accordance with claim 4 wherein said incrementaldrive comprises a plurality of pistons in cylinders connected in aseries, and said means for arresting comprises means for clamping thedistal end of said series to be stationary relative to said fixed memberduring cocking of said damping means.
 7. Apparatus in accordance withclaim 4 wherein a control system is coupled to said damping means andsaid incremental drive for automatically cocking said damping meansprior to each motion of said incremental drive and subsequentlyautoMatically engaging said selectively releasable means for positivelypositioning said movable member.